Magnetostratigraphy of the Collepardo Late Pliocene faunal assemblage (Early Villafranchian Triversa Faunal Unit), Ernici Mts., Central Italy

The chronological attribution of the Collepardo mammal faunal site (Ernici Mts., Central Italy) has been disputed for a long time. Recent studies have attributed the faunal site to the Early Villafranchian Triversa Faunal Unit (FU), on the base of the presence of Agriotherium cf. insigne, Sus arvernensis and Pseudodama lyra. In this paper we present magnetostratigraphic results from 27 cores, sampled in a 10 m thick stratigraphic section across the breccia layers and the interspersed red silty clays and travertine layer containing mammal fossils. In all the samples a normal polarity Characteristic Remanent Magnetization (ChRM) component has been isolated. The presence of magnetite as main magnetic carrier and the consistency of ChRM direction throughout different lithologies strongly suggest a primary origin of the isolated component. Taking into consideration the fossil chronological distribution, the normal polarity magnetozone can be correlated with one of the normal magnetic polarity subchrons within the 2An (Gauss) in the GPTS reference scale, corresponding with Early Villafranchian stage in the continental chronology. Our results support the attribution of the Collepardo mammal assemblage to the Triversa FU and, therefore, the "Travertine and Breccias" deposits to the Late Pliocene (Piacenzian).